Hi there @FrancescoA , welcome to the Community!
From your exception, it sounds like you’ve reached the connection limit for your Solace broker. Or more specifically: you’ve reached the configured connection limit for the specific Message VPN that you are connecting to.
These are essentially the TCP connections from your client apps into Solace. This is not necessarily how many queues you have connected to, as a single connection can connect to multiple queues. But this would depend on how the Boomi binder is configured. Does it force a 1-to-1 connection-to-queue-bind configuration? I’m not sure.
Do you have any visibility of the broker? Are you running it yourself, or using Solace Cloud? There are metrics and logs you can go look at. Perhaps some misconfiguration in an app is causing it to spawn too many connections and using up all the resources?